Synergistic effect of zinc selenide-reduced graphene oxide towards enhanced solar light-responsive photocurrent generation and photocatalytic 4-nitrophenol degradation

Herein, we report the in situ synthesis of zinc selenide (ZnSe)-decorated reduced graphene oxide (RGO) by a simple one-step solvothermal reaction for application in large-area, thin-film photodetector devices and photocatalytic 4-nitrophenol degradation. The photoresponsivity of the RGO-ZnSe photodetector is three orders of magnitude higher than that of controlled ZnSe. The ac transport mechanism in the composite reveals that its electrical conduction is modulated by a temperature-independent universal function. An EIS study confirmed the influence of RGO on the conductivity and charge transfer in the RGO-ZnSe composite. The photocatalytic degradation efficiency of the composite is four times higher than that of controlled ZnSe. In the RGO-ZnSe composite, RGO acts as a solid-state electron mediator, which efficiently collects the photo-induced electrons from the conduction band of ZnSe and subsequently hinders electron-hole recombination in ZnSe. This study explores the role of RGO-ZnSe synergy in achieving better photoresponse and photocatalytic performance. The RGO-ZnSe composite may lead to new possibilities in solar energy-harvesting applications and photocatalytic degradation of different non-self-sensitizing water pollutants.